This invention is directed to a wetness indicating composition having improved colorant retention and to wearable articles comprising this wetness indicating composition.
Wearable and absorbent articles such as diapers are well known in the art. Absorbent articles typically have an absorbent core, which is held or positioned against the body of the wearer during use by a fastening system, such that the article catches the bodily exudates. Typical absorbent articles include a topsheet facing the wearer, which permits fluid exudates to pass through, and a backsheet, which prevents the exudates from escaping from the absorbent article.
Many advances have been made in the art since the introduction of the disposable absorbent article including the introduction of wetness indicating compositions associated with the inside surface of the outer cover of the article. These compositions comprise a colorant adapted to change in appearance, i.e., appear, disappear, change color, etc., upon contact with urine in the article. However, these compositions typically do not sufficiently retain the colorant within the composition, resulting in leaching of the colorant from the composition and into portions of the wearable article or onto the wearer. Certain attempts have been made in the art to retain the colorant, such as incorporating the colorant into adhesive compositions having high melting temperatures. However, the prior art fails to provide urine-indicating compositions having sufficient colorant retention performance. Thus, it would be desirable to provide wetness indicating compositions having minimal or zero leaching of the colorant from the carrier matrix. It would also be desirable to provide absorbent articles comprising these urine-indicating compositions.
The present invention is directed to a wetness indicating composition comprising a colorant disposed in a carrier matrix. The colorant provides a visible signal when activated by urine. The colorant resists leaching from the carrier matrix by being chemically bound or by being bound by intermolecular forces to a component of the carrier matrix.